CS 342 Quiz

1. Consider the following Prolog program
  (infer (sum 0 X X))
  (infer (sum (s X) Y (s Z)) from (sum X Y Z))

What is printed by each of the following queries?
  (a) (infer? (sum 0 0 0))



  (b) (infer? (sum (s (s 0)) (s (s (s 0))) W) (print (answer: W)))



  (c) (infer? (sum (s (s 0)) D (s (s (s (s (s 0)))))) (print (answer: D)))



2. Consider adding the following to the above Prolog program
   (infer (prod 0 X 0) from (print (prod-base X)))
   (infer (prod (s X) Y Z)
	from (print (prod-ind X Y Z))
	     (prod X Y W) (print (prod-W= W)) (sum  Y W Z))


What is printed by each of the following queries?
  (a) (infer? (prod 0 0 0))





  (b) (infer? (prod (s (s 0)) (s (s (s 0))) W) (print (answer: W)))





  (c) (infer? (prod (s (s 0)) D (s (s (s (s (s (s 0))))))) (print (answer: D)))








3. Write a prolog relation find-last such that the query
  (infer? (find-last (cons 2 (cons 3 nil)) X) (print X))
prints 3.